Is there a power jack on this gizmo anywhere?

If there is, a "wall wart" type of 12VDC power supply could be used, but it has to match (1) size of plug fits jack in the speaker, (2) polarity is correct (usually, the center is POSITIVE, but not always) and (3) it can supply enough current.

... or this universal animal, that can dish out up to 2 amps @ 12VDC might be adequate. Read the product notes if you have a "center negative" jack.